Wide-temperature-range cascade multifunctional industrial heat pump system and operation control method

Abstract

The application provides a wide-temperature-range cascade multifunctional industrial heat pump system and an operation control method, relates to the technical field of heat pump product design and operation control, and aims to improve the working condition adaptability and energy on-demand distribution flexibility of the industrial heat pump under cold and heat demand in different production stages.

Description

Technical Field

[0001] This invention relates to the field of heat pump product design and operation control technology, and in particular to a wide-temperature-range cascade multifunctional industrial heat pump system and its operation control method. Background Technology

[0002] Energy conservation and emission reduction in the industrial sector have become an important direction for energy transformation and green development. In fields such as chemical engineering, food processing, pharmaceuticals, and textile printing and dyeing, traditional coal-fired and gas-fired boilers are facing elimination due to their high energy consumption and high emissions. Industrial steam heat pumps, as a core technology to replace traditional coal-fired and gas-fired boilers, effectively reduce energy consumption and carbon emissions, and have broad application prospects and value.

[0003] However, different industrial scenarios and production stages have significantly different demands for heating and cooling. Existing equipment typically employs a fixed-function design, making it impossible to flexibly switch operating modes according to actual working conditions. It also struggles to achieve on-demand allocation and priority supply of heating and cooling, resulting in low utilization rates for some equipment and overall low system efficiency. Existing conventional heat pumps or integrated heating and cooling systems can usually only stably provide medium- and low-temperature hot water or steam within a limited temperature range. They struggle to achieve stable high-temperature hot water or even high-temperature steam output within the same system, and often experience efficiency degradation or insufficient system stability under high-temperature output conditions. Summary of the Invention

[0004] To address the aforementioned issues, this invention proposes a wide-temperature-range cascade multifunctional industrial heat pump system and its operation control method, which enhances the adaptability of industrial heat pumps to different production stages under varying heating and cooling demands and the flexibility of energy allocation on demand.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a wide-temperature-range cascade multifunctional industrial heat pump system, comprising: The low-temperature stage subsystem consists of a low-temperature stage compressor, a low-temperature stage condenser, a low-temperature stage throttling element, and a low-temperature stage evaporator connected in sequence to form a loop; the water-side interface of the low-temperature stage condenser is selectively connected to a medium-temperature hot water tank or a medium-temperature drying heat exchanger via a medium-temperature water three-way valve; the water-side interface of the low-temperature stage evaporator is selectively connected to a chilled water tank or a chilled water heat exchanger via a chilled water three-way valve. The high-temperature stage subsystem consists of a high-temperature stage compressor, a high-temperature stage condenser, a high-temperature stage throttling element, and a high-temperature stage evaporator connected in sequence to form a loop; the water-side interface of the high-temperature stage condenser is selectively connected to a high-temperature hot water tank or a high-temperature drying heat exchanger via a high-temperature three-way valve; the water-side interface of the high-temperature stage evaporator is selectively connected to a cold water tank or a cold water heat exchanger via a cold water three-way valve. The cascade heat exchange unit includes a refrigerant-side heat exchanger, whose low-temperature side passage is connected between the outlet of the low-temperature stage compressor and the low-temperature stage condenser, and the two ends of the passage are respectively provided with solenoid valves, and whose high-temperature side passage is connected between the high-temperature stage evaporator and the suction port of the high-temperature stage compressor. The room includes a drying / refrigeration area with a room body equipped with air supply and return vents. The medium-temperature drying heat exchanger, chilled water heat exchanger, high-temperature drying heat exchanger, and cold water heat exchanger are all located within the room body or connected to its air duct.

[0006] Secondly, the present invention provides an operation control method for a wide temperature range cascade multifunctional industrial heat pump system, including a low temperature stage system operation mode, a high temperature stage system operation mode and a cascade system operation mode. In the independent operation mode of the low-temperature stage, the low-temperature stage compressor is started, allowing the refrigerant to circulate in the low-temperature stage subsystem; the heat output of the low-temperature stage condenser is selected to the medium-temperature hot water tank or the medium-temperature drying heat exchanger through the medium-temperature water three-way valve, and the low-temperature stage evaporator absorbs heat from the chilled water tank or the chilled water heat exchanger through the refrigeration three-way valve; the operating frequency of the low-temperature stage compressor is adjusted according to the first target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the independent operation mode of the high-temperature stage, the high-temperature stage compressor is started, allowing the refrigerant to circulate in the high-temperature stage subsystem; the high-temperature three-way valve is used to select whether the heat from the high-temperature stage condenser is output to the high-temperature hot water tank or the high-temperature drying heat exchanger, and the cold water three-way valve is used to select whether the high-temperature stage evaporator absorbs heat from the cold water tank or the cold water heat exchanger; the operating frequency of the high-temperature stage compressor is adjusted according to the second target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the cascade operation mode, the low-temperature stage compressor and the high-temperature stage compressor are started simultaneously, and the refrigerant-side heat exchanger is controlled to participate in heat exchange. The heat absorbed by the low-temperature stage subsystem is transferred to the high-temperature stage subsystem through the refrigerant-side heat exchanger, and then output after being upgraded by the high-temperature stage subsystem. The heat is output to the high-temperature hot water tank through the high-temperature three-way valve, and the cold energy is output to the chilled water tank through the refrigeration three-way valve. The operating frequency of each compressor is adjusted according to the third target temperature deviation.

[0007] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the operation control method described in the second aspect.

[0008] Fourthly, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the operation control method described in the second aspect.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention constructs a wide-temperature-range water loop covering chilled water, medium-temperature water, cold water, and high-temperature hot water / steam. The unit can operate independently as a low-temperature stage system to absorb heat from low-temperature (cooling) chilled water to produce hot water; it can also operate as a high-temperature stage system to absorb heat from relatively high-temperature (cooling) cold water to produce high-temperature hot water / steam (flash evaporation); or it can operate as a cascade system to absorb heat from low-temperature chilled water to produce high-temperature hot water / steam (flash evaporation). Under any operating condition, it simultaneously obtains both cooling and heating energy with a single unit of electricity consumption. By activating the relatively efficient system according to different application conditions, it not only meets functional requirements but also effectively improves the unit's system efficiency and saves energy.

[0010] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute a limitation thereof.

[0011] Figure 1 A schematic diagram of a wide-temperature-range cascade multifunctional industrial heat pump system provided in an embodiment of the present invention; Figure 2 A flowchart of an operation control method for a wide-temperature-range cascaded multifunctional industrial heat pump cryogenic stage system provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the operation control method of a wide-temperature-range cascaded multifunctional industrial heat pump high-temperature stage system provided in this embodiment of the invention; Figure 4 A flowchart of an operation control method for a wide-temperature-range cascade multifunctional industrial heat pump cascade system provided in an embodiment of the present invention; The components are as follows: 1-Room body, 2-Supply air fan, 3-Supply air outlet, 4-Return air outlet, 5-Chiller water heat exchanger, 6-Medium-temperature drying heat exchanger, 7-Cold water heat exchanger, 8-High-temperature drying heat exchanger, 9-Low-temperature stage compressor, 10-High-temperature stage compressor, 11-Chiller water tank, 12-Medium-temperature hot water tank, 13-Cold water tank, 14-High-temperature hot water tank, 15-Refrigerant-side heat exchanger, 16-Low-temperature stage condenser, 17-Low-temperature stage evaporator, 18-High-temperature stage condenser. 19-High-temperature stage evaporator, 20-Low-temperature stage throttling element, 21-High-temperature stage throttling element, 22-First solenoid valve, 23-Second solenoid valve, 24-Chiller water pump, 25-Medium-temperature water pump, 26-Cold water pump, 27-High-temperature water pump, 28-Chiller water supply pump, 29-Medium-temperature water supply pump, 30-Cold water supply pump, 31-Steam valve, 32-Chiller three-way valve, 33-Medium-temperature water three-way valve, 34-Cold water three-way valve, 35-High-temperature three-way valve, 36-Throttle valve. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Example 1 like Figure 1 As shown, this embodiment provides a wide-temperature-range cascade multifunctional industrial heat pump system, including: The low-temperature stage subsystem consists of a low-temperature stage compressor, a low-temperature stage condenser, a low-temperature stage throttling element, and a low-temperature stage evaporator connected in sequence to form a loop; the water-side interface of the low-temperature stage condenser is selectively connected to a medium-temperature hot water tank or a medium-temperature drying heat exchanger via a medium-temperature water three-way valve; the water-side interface of the low-temperature stage evaporator is selectively connected to a chilled water tank or a chilled water heat exchanger via a chilled water three-way valve. The high-temperature stage subsystem consists of a high-temperature stage compressor, a high-temperature stage condenser, a high-temperature stage throttling element, and a high-temperature stage evaporator connected in sequence to form a loop; the water-side interface of the high-temperature stage condenser is selectively connected to a high-temperature hot water tank or a high-temperature drying heat exchanger via a high-temperature three-way valve; the water-side interface of the high-temperature stage evaporator is selectively connected to a cold water tank or a cold water heat exchanger via a cold water three-way valve. The cascade heat exchange unit includes a refrigerant-side heat exchanger, whose low-temperature side passage is connected between the outlet of the low-temperature stage compressor and the low-temperature stage condenser, and the two ends of the passage are respectively provided with solenoid valves, and whose high-temperature side passage is connected between the high-temperature stage evaporator and the suction port of the high-temperature stage compressor. The room includes a drying / refrigeration area with a room body equipped with air supply and return vents. The medium-temperature drying heat exchanger, chilled water heat exchanger, high-temperature drying heat exchanger, and cold water heat exchanger are all located within the room body or connected to its air duct.

[0014] Specifically, the system includes a low-temperature stage compressor 9, a low-temperature stage evaporator 17, a high-temperature stage compressor 10, a high-temperature stage evaporator 19, a refrigerant-side heat exchanger 15, a low-temperature stage condenser 16, a medium-temperature drying heat exchanger 6, a high-temperature stage condenser 18, a high-temperature drying heat exchanger 8, a chilled water heat exchanger 5, a medium-temperature hot water tank 12, a cold water heat exchanger 7, a high-temperature hot water tank 14, a chilled water tank 11, a cold water tank 13, a low-temperature stage throttling element 20, a high-temperature stage throttling element 21, a medium-temperature water pump 25, a chilled water pump 24, a medium-temperature water supply pump 29, a chilled water supply pump 28, a high-temperature water pump 27, a cold water pump 26, a cold water supply pump 30, a chilled water three-way valve 32, a medium-temperature water three-way valve 33, a cold water three-way valve 34, a high-temperature three-way valve 35, a steam valve 31, a throttling valve 36, and a first solenoid valve 22 and a second solenoid valve 23, etc.

[0015] The drying / refrigeration area includes the room body 1, the air supply fan 2, the air supply outlet 3, and the return air outlet 4.

[0016] Depending on different scenarios and functional requirements, it can be used for multiple purposes. Through the operation control system, it can automatically switch between low temperature system operation mode, high temperature system operation mode and cascade system operation mode to achieve on-demand supply of medium temperature hot water, high temperature hot water, steam, cold water and chilled water. At the same time, it can meet multiple functional requirements such as high temperature drying, low temperature drying, cooling, cooling and refrigeration, high dew point dehumidification, low dew point dehumidification and production process cold and heat source.

[0017] In the low-temperature stage system operation mode, the low-temperature stage compressor 9, the low-temperature stage condenser 16, and the low-temperature stage evaporator 17 operate, while the high-temperature stage system stops operating. The system operation process is as follows: Figure 2 As shown, the details are as follows: When the low-temperature stage compressor 9 operates, the first solenoid valve is closed and the second solenoid valve is open, and the refrigerant-side heat exchanger 15 does not exchange heat. The high-temperature, high-pressure refrigerant discharged from the low-temperature stage compressor 9 enters the low-temperature stage condenser 16 to release heat, and then transfers heat to the medium-temperature hot water system through the medium-temperature water pump 25; after the refrigerant is depressurized by the throttling element 20, it enters the low-temperature stage evaporator 17 to evaporate and absorb heat, and then absorbs heat from the chilled water system through the chilled water pump to complete the refrigeration cycle, thereby achieving synchronous output of medium-temperature hot water and chilled water. The control method for the low-temperature stage system operation mode is as follows: The first step is to set the target temperature T for the medium-temperature hot water. m_set Target temperature of chilled water T f_set Target water volume G for medium-temperature hot water m_set Target volume of chilled water G f_set Target running time t after reaching the required target temperature _set Target air temperature T in the drying / refrigeration area _set and target dew point temperature T d_set The target values ​​are all determined based on the requirements of industrial production processes. The second step is to monitor the temperature T of the medium-temperature hot water in real time. m chilled water temperature T f Medium-temperature hot water volume G m chilled water volume G f The operating time t after the conditions are met, the air temperature T in the drying / refrigeration area, and the air dew point temperature T d ; The third step is to calculate the first target temperature deviation according to the formula based on the deviation between the target value and the actual value. This deviation is used to adjust the operating frequency of the low-temperature compressor and to switch the conduction direction of each three-way valve according to the environmental conditions. The first target temperature deviation includes the target deviation of the medium-temperature hot water temperature, the chilled water temperature, the temperature deviation, and the dew point deviation.

[0018] Specifically, the deviation of the medium-temperature hot water from the target temperature is calculated according to the formula. f m = (T m_set -T m ) / T m_set ×100% and chilled water temperature f f = (T f_set -T f ) / T f_set ×100%, using the deviation as the input signal to the PID controller, adjusts the compressor frequency through the PID algorithm, dynamically regulating the compressor's operating frequency to control the water temperature in the medium-temperature hot water tank and the chilled water tank. The actual temperature T of the medium-temperature hot water... m Below the set temperature T m_set hour, f m A value greater than 0 indicates insufficient heat output from the low-temperature stage condenser. PID control is used to increase the compressor frequency and refrigerant circulation, thereby enhancing the heat dissipation capacity of the low-temperature condenser and raising the temperature of the medium-temperature hot water. When the actual chilled water temperature T... f Higher than the set temperature T f_set hour, f f A value less than 0 indicates insufficient cooling capacity on the low-temperature stage evaporator side. PID control is used to increase the compressor's operating frequency, thereby enhancing the evaporative heat absorption capacity and lowering the chilled water temperature. f m , f f When the value gradually approaches 0, it indicates that the output capacity of the cold and heat source side meets the set requirements, and the compressor frequency is adjusted by PID control to maintain stability.

[0019] Calculate the temperature deviation using the formula. f T = (T _set -T) / T_set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, and based on temperature deviation f T and dew point deviation f d By adjusting the opening degrees of the medium-temperature water three-way valve 33 and the chilled water three-way valve 32 through PID control, the flow rates of hot and cold water entering the process heat exchanger are changed, thereby achieving stable control of temperature and humidity parameters in the process area; when the actual temperature of the drying chamber is lower than the target temperature, f T A value greater than 0 indicates insufficient heating. The PID control system increases the opening of the medium-temperature water three-way valve 33 to increase the hot water flow into the medium-temperature drying heat exchanger 6, thereby increasing the heating capacity. When the drying chamber temperature approaches the set value, the PID control gradually decreases the opening of the medium-temperature water three-way valve 33 to match the heating supply with the actual heat load. When the air dew point temperature is higher than the target dew point temperature, f d <0 indicates insufficient air dehumidification capacity. The PID control system increases the opening of the chilled water three-way valve 32 to increase the flow rate of chilled water entering the chilled water heat exchanger 5, thereby increasing the condensation dehumidification capacity and lowering the air dew point temperature. When the dew point temperature reaches the target value, the PID control reduces the opening of the chilled water three-way valve 32 to reduce the cooling capacity and avoid excessive cooling.

[0020] Fourthly, if the drying / heating constant temperature priority is selected, the PID control system automatically adjusts the medium-temperature water three-way valve 33 to circulate water to the medium-temperature drying heat exchanger 6 for drying or heating based on the deviation. When the air temperature T reaches the target value T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _set If the required temperature is met, the unit will maintain stable operation; otherwise, it will stop operating. If medium-temperature hot water is needed, the PID control will adjust the medium-temperature water three-way valve, and simultaneously operate the medium-temperature water supply pump to provide the required medium-temperature hot water, achieving the target water volume G. m_set Then, stop operating; if the production process is selected to prioritize hot water supply, then the other process is selected. Fifth, if low dew point dehumidification / cooling refrigeration is selected as the priority, the PID control system automatically adjusts the refrigeration three-way valve 32 to circulate water to the chilled water heat exchanger 5 according to the deviation, starting the dehumidification or cooling operation. When the air temperature T reaches the target value T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _setIf the requirements are met, the unit will maintain stable operation; otherwise, it will stop operating. If chilled water is needed, the PID control will adjust the chilled water three-way valve and simultaneously operate the chilled water supply pump to provide the required chilled water to achieve the target water volume G. f_set Then, stop operation; if the production process prioritizes supplying chilled water, then the other process does not.

[0021] In the high-temperature stage system operation mode, the high-temperature stage compressor, high-temperature stage condenser, and high-temperature stage evaporator operate, while the low-temperature stage system stops operating. The system operation flow is as follows: The high-temperature stage compressor operates, and the high-temperature, high-pressure refrigerant discharged from the compressor enters the high-temperature stage condenser to release heat. This heat is then transferred to the high-temperature hot water system via a high-temperature water pump or used to generate steam via a high-temperature hot water tank. After the refrigerant is depressurized by a throttling element, it enters the high-temperature stage evaporator to evaporate and absorb heat. This heat is then absorbed from the cold water system via a cold water pump, completing the refrigeration cycle and achieving synchronous output of steam and cold water. The control method for the high-temperature stage system operation mode is as follows: Figure 3 As shown, the details are as follows: The first step is to set the target steam temperature T. s_set Target temperature of cold water T c_set Steam target quantity G s_set Cold water target volume G c_set Target running time t after reaching the required target temperature _set Target air temperature T in the drying / cooling zone _set and target dew point temperature T d_set The target values ​​are all determined based on the requirements of industrial production processes. The second step is to monitor the steam temperature T in real time. s Cold water temperature T c Steam quantity G m Cold water volume G f The operating time t after the conditions are met, the air temperature T in the drying / cooling zone, and the air dew point temperature T d ; The third step is to calculate the second target temperature deviation according to the formula based on the deviation between the target value and the actual value. This deviation is used to adjust the operating frequency of the high-temperature stage compressor and to switch the conduction direction of each three-way valve according to the environmental conditions. The second target temperature deviation includes the steam temperature target deviation, the cold water temperature, the temperature deviation, and the dew point deviation.

[0022] Specifically, the deviation from the steam temperature target is calculated according to the formula. f s = (T s_set -T s ) / T s_set ×100% and cold water temperature f c = (T c_set -T c ) / Tc_set ×100%, using the deviation as the input signal for the PID controller, the PID algorithm adjusts the compressor frequency to control the water temperature in the high-temperature hot water tank and cold water tank; when the actual temperature T of the high-temperature hot water / steam... s Below the set temperature T s_set hour, f s A value greater than 0 indicates insufficient heat output from the high-temperature stage condenser. PID control is used to increase the operating frequency of the high-temperature stage compressor 10, thereby increasing the refrigerant circulation and enhancing the heat release capacity of the high-temperature stage condenser 18, thus raising the temperature of the high-temperature hot water / steam. When the actual temperature of the cold water T... c Higher than the set temperature T c_set hour, f c A value less than 0 indicates insufficient cooling capacity on the high-temperature stage evaporator side. PID control is used to increase the operating frequency of the high-temperature stage compressor 10, thereby increasing the heat absorption capacity of the high-temperature stage evaporator 19 and lowering the chilled water temperature. f s , f c As the temperature gradually approaches zero, it indicates that the output capacity of the high-temperature stage's heat source and cold source side meets the set requirements, and the PID control of the high-temperature stage compressor 10 is operating stably. The temperature deviation is calculated according to the formula. f T =(T _set -T) / T _set ×100% and dew point deviation f d =(T d_set -T d ) / T d_set ×100%, temperature deviation controlled by PID. f T and dew point deviation f d Adjust the system's heating, cooling, and dehumidification capabilities; when the actual temperature of the drying room is lower than the target temperature... f T A value greater than 0 indicates insufficient high-temperature heating. The PID control system increases the opening of the high-temperature water three-way valve (35°C) to increase the flow rate of high-temperature hot water into the high-temperature drying heat exchanger (8), thereby increasing the heating capacity. As the drying chamber temperature gradually approaches the target value, the PID control system decreases the opening of the high-temperature water three-way valve (35°C) to match the actual heat load of the drying chamber. When the air dew point temperature is higher than the target dew point temperature... f d<0 indicates insufficient air dehumidification capacity. The PID control system increases the opening of the chilled water three-way valve 34 to increase the flow rate of chilled water into the chilled water heat exchanger 7, thereby increasing the air condensation and dehumidification capacity and reducing the air moisture content and dew point temperature. When the air dew point temperature reaches the target value, the PID control gradually decreases the opening of the chilled water three-way valve 34 to reduce the cooling capacity and avoid overcooling.

[0023] Fourthly, if high-temperature drying / heating with constant temperature is selected as the priority, the high-temperature three-way valve is adjusted by PID control according to the deviation, circulating high-temperature hot water to the high-temperature drying heat exchanger for high-temperature drying or heating; when the air temperature T reaches the target air temperature T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _set If the requirements are met, the unit will maintain stable operation; otherwise, it will stop operating. If steam supply is needed, the high-temperature three-way valve will be automatically adjusted, and the steam valve will be opened simultaneously to provide the required steam to the production process system, achieving the target water volume G. s_set Then, operation stops; if the production process is selected to prioritize steam supply, then the opposite applies. Fifth, if high dew point dehumidification / cooling priority is selected, the system uses PID control to adjust the chilled water three-way valve according to the deviation, circulating chilled water to the chilled water heat exchanger for dehumidification or cooling; when the air temperature T reaches the target air temperature T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _set If the requirements are met, the unit will maintain stable operation; otherwise, it will stop operating. If chilled water is needed, the chilled water three-way valve will automatically adjust, and the chilled water supply pump will operate simultaneously to provide the required chilled water to achieve the target water volume G. c_set Then, stop operation; if the production process prioritizes supplying cooling water, then the opposite applies.

[0024] In the cascade system operation mode, the low-temperature stage system and the high-temperature stage system operate simultaneously. The first solenoid valve is open, and the second solenoid valve is closed. The refrigerant exchanges heat in the refrigerant-side heat exchanger, and the low-temperature stage condenser does not release heat. The system operation flow is as follows: The refrigerant absorbs heat from the chilled water system in the low-temperature stage evaporator, enters the low-temperature stage compressor for compression and temperature and pressure increase, and then enters the refrigerant-side heat exchanger to transfer the absorbed low-grade heat to the high-temperature stage evaporator. The high-temperature stage evaporator absorbs heat released from the low-temperature stage system, and then the refrigerant is further compressed by the high-temperature stage compressor to reach a high-temperature and high-pressure state. It then enters the high-temperature stage condenser to release heat, and the heat is transferred to the high-temperature hot water system or high-temperature hot water tank device by a high-temperature water pump, thereby producing high-temperature hot water or steam. The control method for the cascade system operation mode is as follows: Figure 4 As shown, the details are as follows: The first step is to set the target steam temperature T. s_set Target temperature of chilled water T f_set Steam target quantity G s_set Target volume of chilled water G f_set Target running time t after reaching the required target temperature _set Target air temperature T in the drying / refrigeration area _set and target dew point temperature T d_set Each target parameter is set according to the requirements of industrial production processes; The second step is to monitor the steam temperature T in real time. s chilled water temperature T f Steam quantity G m chilled water volume G f The operating time t after the conditions are met, the air temperature T in the drying / refrigeration area, and the air dew point temperature T. d ; The third step is to calculate the third target temperature deviation according to the formula based on the deviation between the target value and the actual value. This deviation is used to adjust the operating frequency of each compressor and switch the conduction direction of each three-way valve according to the environmental conditions. The third target temperature deviation includes the steam temperature target deviation, chilled water temperature, temperature deviation, and dew point deviation.

[0025] Specifically, the deviation from the steam temperature target is calculated according to the formula. f s = (T s_set -T s ) / T s_set ×100% and chilled water temperature f f = (T f_set -T f ) / T f_set ×100%, the deviation is used as the input signal of the PID controller. The compressor frequency is adjusted through PID control to control the water temperature in the high-temperature hot water tank and the chilled water tank; when the actual temperature T of the high-temperature hot water / steam is... s Below the set temperature T s_set hour, f s A value greater than 0 indicates insufficient heat output from the high-temperature stage condenser. PID control is used to increase the operating frequency of the high-temperature stage compressor 10, thereby increasing the refrigerant circulation and enhancing the heat release capacity of the high-temperature stage condenser 18, thus raising the temperature of the high-temperature hot water / steam. When the actual temperature of the cold water T... f Higher than the set temperature T f_set hour, f fA value less than 0 indicates insufficient cooling capacity on the high-temperature stage evaporator side. PID control is used to increase the operating frequency of the high-temperature stage compressor 10, thereby increasing the heat absorption capacity of the evaporator 19 and lowering the chilled water temperature. f s , f f When the value gradually approaches 0, it indicates that the output capacity of the high-temperature stage cold and heat source side meets the set requirements, and the compressor operates stably through PID control.

[0026] Calculate the temperature deviation using the formula. f T =(T _set -T) / T _set ×100% and dew point deviation f d =(T d_set -T d ) / T d_set ×100%, and based on temperature deviation f T and dew point deviation f d Adjust the system's operating status; when the actual temperature of the drying oven is lower than the target temperature... f T A value greater than 0 indicates insufficient heating capacity. The PID control system prioritizes adjusting the opening of the high-temperature water three-way valve 35 to increase the flow rate of high-temperature hot water entering the high-temperature drying heat exchanger 8, thereby increasing the heating capacity. As the drying chamber temperature gradually approaches the set value, the PID control reduces the opening of the high-temperature water three-way valve 35 to match the actual heat load of the drying chamber. When the actual air dew point temperature is higher than the target dew point temperature... f d <0 indicates insufficient air dehumidification capacity. The PID control system adjusts the opening of the chilled water three-way valve 32 to increase the flow rate of cold water entering the chilled water heat exchanger 5, thereby increasing the air condensation and dehumidification capacity and lowering the air dew point temperature. When the dew point temperature reaches the target value, the PID control reduces the opening of the chilled water three-way valve 32 to reduce the cooling capacity and avoid excessive cooling.

[0027] Fourthly, if high-temperature drying / heating with constant temperature is selected as the priority, the high-temperature three-way valve is adjusted by PID control according to the deviation, circulating high-temperature hot water to the high-temperature drying heat exchanger for high-temperature drying or heating; when the air temperature T reaches the target air temperature T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _set If the requirements are met, the unit will maintain stable operation; otherwise, it will stop operating. If steam supply is needed, the high-temperature three-way valve will be automatically adjusted, and the steam valve will be opened simultaneously to provide the required steam to the production process system, achieving the target water volume G.s_set Then, operation stops; if the production process is selected to prioritize steam supply, then the opposite applies. Fifth, if low dew point dehumidification / cooling refrigeration is selected as the priority, the system uses PID control to adjust the refrigeration three-way valve to circulate water to the chilled water heat exchanger to start dehumidification or cooling, based on the deviation degree. When the air temperature T reaches the target value T... _set And the air dew point temperature T d To reach the target dew point temperature T d_set Afterwards, if there is a target running time t _set If the requirements are met, the unit will maintain stable operation; otherwise, it will stop operating. If chilled water is needed, the chilled water three-way valve will automatically adjust, and the chilled water supply pump will operate simultaneously to provide the required chilled water to reach the target water volume G. f_set Then, stop operation; if the production process prioritizes supplying chilled water, then the other process does not.

[0028] In this embodiment, the system first ensures that it has the capacity to provide cold and heat sources to meet the process requirements by adjusting the compressor frequency, and then the system achieves a reasonable distribution of cold and heat to different process ends by adjusting the three-way valve. The two work together to complete the system operation control, which improves the stability of the system's cold and heat supply and the accuracy of load adaptation of multiple process branches.

[0029] As one implementation method, the application process of the system provided in this embodiment is illustrated using the coconut processing process as an example. The coconut processing process typically includes drying, constant temperature heating, Maillard reaction, cooling, cold storage, cooking, and pasteurization. Since different process stages have different requirements for heating temperature, cooling temperature, and air humidity, different operating modes need to be switched according to process requirements to meet the heating and cooling needs during production.

[0030] 1) Pre-drying process When entering the initial drying stage, the low-temperature system can be activated to dehydrate and dehumidify the coconut meat.

[0031] The low-temperature stage compressor 9 starts running, and at the same time controls the first solenoid valve 22 to close and the second solenoid valve 23 to open, so that the refrigerant-side heat exchanger 15 does not participate in heat exchange.

[0032] The high-temperature and high-pressure refrigerant discharged from the low-temperature compressor 9 enters the low-temperature condenser 16 to release heat, and is then transported to the medium-temperature drying heat exchanger 6 by the medium-temperature water pump 25 to heat the air in the drying room 1, so that the moisture in the coconut meat continuously vaporizes and enters the air.

[0033] During operation, if it is necessary to start the medium-temperature drying heat exchanger 6, the system first sets the target air temperature T of the drying chamber 1. _set (e.g., T) _set =65℃), target dew point temperature T d_set (e.g., T) d_set=15℃), target temperature T for medium-temperature hot water m_set (e.g., T) m_set =65℃), target temperature of chilled water T f_set (e.g., T) f_set =15℃), target water volume for medium-temperature hot water G m_set (e.g. G) m_set =10t), target chilled water volume G f_set (e.g. G) f_set =10t) ， After the conditions are met, the target running time t _set (e.g. t) _set =10h), and monitor the temperature T of the medium-temperature hot water in drying room 1 in real time. m chilled water temperature T f Medium-temperature hot water volume G m chilled water volume G f After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d And based on the temperature deviation f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, the opening degree of the medium-temperature water three-way valve 33 is dynamically adjusted by PID control to increase the hot water flow rate entering the medium-temperature water heat exchanger 6, thereby maintaining a stable drying room temperature. When f T and f d When the flow rate approaches 0, start recording the running time t, gradually reduce the flow rate on the heating side and transfer the remaining heat to the medium-temperature hot water tank 12, and when t ≥ t _set At this point, the system completes the medium-temperature drying stage and enters the next operating stage.

[0034] If the current operating conditions do not require the participation of the medium-temperature drying heat exchanger 6, the system determines whether there is a demand for medium-temperature hot water in the production process; if there is a demand for medium-temperature hot water, the system determines the temperature deviation based on the target temperature deviation of the medium-temperature hot water. f m = (T m_set -T m ) / T m_set ×100%, the compressor frequency is adjusted by PID control. When f f When the value is greater than 0, the compressor operating frequency is increased to improve the overall heating capacity of the system; when f fWhen the temperature approaches 0, maintain stable compressor operation. Adjust the opening of the medium-temperature water three-way valve 33 using PID control to distribute heat to the production process loop as needed. Turn on the medium-temperature water supply pump 29 and determine G. m≥ G m_set， If medium-temperature water supply is not required, proceed to the next stage.

[0035] Then, the low dew point dehumidification stage begins. The refrigerant is depressurized by the throttling element 20 and enters the low-temperature evaporator 17 to absorb heat. Chilled water is produced by the chilled water pump 24 and sent to the chilled water heat exchanger 5, which cools the humid air to below the dew point temperature, causing water vapor in the air to condense and precipitate.

[0036] During this process, if it is necessary to start the chilled water heat exchanger 5, the temperature deviation should be considered. f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100% PID control is applied to the dehumidification process. f T and f d When all values ​​are less than 0, the PID control system prioritizes increasing the opening of the chilled water three-way valve 32 to improve the heat exchange capacity of the chilled water; when f T and f d When the dehumidification time approaches 0, start recording the running time t and maintain stable operation at the current dehumidification state; when t ≥ t _set When the system completes this phase of operation, it proceeds to the next phase. If the current operating conditions do not require the participation of chilled water heat exchanger 5, the system determines whether there is a demand for hot or cold water in the production process; if there is a demand for chilled water, it determines the temperature deviation based on the chilled water temperature target deviation. f f = (T f_set -T f ) / T f_set ×100%, the compressor frequency is adjusted by PID control. When f f When the value is less than 0, the compressor operating frequency is increased to improve the overall cooling capacity of the system; when... f f When the temperature approaches 0, the compressor is kept in a stable operating state through PID control. The opening of the chilled water three-way valve 32 is adjusted to distribute the cooling capacity to the production process loop as needed. The chilled water supply pump 28 is turned on, and G is judged. f ≥G f_setIf the supply of chilled water is not required, the process will stop and proceed to the next stage.

[0037] While the low-temperature stage system meets the drying requirements, the high-temperature stage system can operate independently for coconut juice production. During high-temperature stage operation, if it is necessary to start the high-temperature drying heat exchanger 8, the target air temperature T in the drying chamber 1 should be set. _set (e.g., T) _set =65℃), target dew point temperature T d_set (e.g., T) d_set =25℃), target temperature T for high-temperature hot water / steam s_set (e.g., T) s_set =140℃), target temperature of cold water T c_set (e.g., T) c_set =85℃), target quantity of high-temperature hot water / steam G s_set (e.g. G) s_set =10t), target cold water volume G c_set (e.g. G) c_set =10t), target running time t after the condition is met _set (e.g. t) _set =3h), and monitor the high-temperature hot water / steam temperature T of drying room 1 in real time. s Cold water temperature T c Steam quantity G m Cold water volume G c After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d And based on the temperature deviation f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, when f T Greater than 0 f d When the value is less than 0, the PID control system prioritizes the opening of the high-temperature three-way valve to 35 degrees to improve the heat exchange capacity of the high-temperature water; when... f T and f d When the flow rate approaches zero, the running time t is recorded, the heat exchanger flow rate is reduced, and excess heat is introduced into the high-temperature hot water tank 14, thereby stabilizing the output of high-temperature hot water / steam. When t ≥ t _setWhen the current process stage is completed, the system determines that it is ready to proceed to the next stage or stop operation. If the current operating condition does not require the participation of the high-temperature drying heat exchanger 8, it determines whether high-temperature hot water / steam is needed; if high-temperature hot water / steam is needed, it determines the temperature deviation from the target based on the required temperature. f s = (T s_set -T s ) / T s_set ×100%, the compressor frequency is adjusted by PID control. When f s When the value is greater than 0, PID control increases the compressor's operating frequency to improve the overall heating capacity of the system; when... f s When the temperature approaches 0, the compressor maintains stable operation through PID control, adjusts the opening of the high-temperature three-way valve 35 to distribute heat to the production process loop as needed, opens the steam valve 31, and determines G. s ≥G s_set If the supply of high-temperature hot water / steam is not required, the high-temperature hot water / steam supply will be stopped. If the supply of high-temperature hot water / steam is not required, proceed to the next stage.

[0038] After the refrigerant is depressurized by the throttling element 21, it enters the high-temperature evaporator 19 to evaporate and absorb heat, and then produces chilled water via the chilled water pump 26. During this process, when the chilled water heat exchanger 7 needs to be activated, a temperature deviation is set. f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, when f T and f d When the temperature is high, the PID control system prioritizes increasing the opening of the chilled water three-way valve (34) to improve the chilled water heat exchange capacity; when... f T and f d As the temperature approaches zero, the running time t is recorded, and the opening of the three-way valve is automatically reduced to avoid excessive cooling. Simultaneously, stable dehumidification boundary conditions are maintained, thus achieving coordinated control of the drying chamber temperature and dew point. This allows coconut meat dehydration and air dehumidification to proceed simultaneously, completing closed-loop drying without the need for dehumidification. When t ≥ t _set If the current operating condition does not require the participation of the chilled water heat exchanger 7, the system determines whether there is a need for chilled water in the production process; if chilled water is required, the system determines the chilled water temperature deviation from the target. f c = (T c_set -Tc ) / T c_set ×100%, the compressor frequency is adjusted by PID control. When f c When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall cooling capacity of the system; when... f c When the temperature approaches 0, the PID control compressor operates stably, adjusting the opening of the chilled water three-way valve 34 to distribute the cooling capacity to the production process loop as needed, and turning on the chilled water supply pump 30 to determine G. c ≥G c_set If the cold water supply is not required, proceed to the next stage.

[0039] 2) High-temperature drying process in the later stage As drying progresses, the moisture content of the coconut meat gradually decreases, the air dew point temperature drops, and the resistance to moisture migration inside the material increases. Therefore, it is necessary to further increase the drying temperature to promote rapid vaporization of internal moisture. Thus, a cascade system is used.

[0040] The system simultaneously starts the low-temperature compressor 9 and the high-temperature compressor 10, closes the second solenoid valve 23, and opens the first solenoid valve 22. The high-temperature, high-pressure refrigerant discharged from the low-temperature compressor 9 enters the refrigerant-side heat exchanger 15 to release heat, transferring the heat to the high-temperature evaporator 19. After further compression by the high-temperature compressor 10, the high-temperature condenser 18 outputs high-temperature hot water / steam, which is then transported to the high-temperature drying heat exchanger 8 by the high-temperature water pump 27. During operation, if the high-temperature drying heat exchanger 8 needs to be started, the system first sets the target air temperature T of the drying chamber 1. _set (e.g., T) _set =115℃), target dew point temperature T d_set (e.g., T) d_set =15℃), target temperature T for high-temperature hot water / steam s_set (e.g., T) s_set =115℃), target temperature of chilled water T f_set (e.g., T) f_set =15℃), target quantity of high-temperature hot water / steam G s_set (e.g. G) s_set =10t), target chilled water volume G f_set (e.g. G) f_set =10t), target running time t after the condition is met _set (e.g. t) _set =3h), and monitor the high-temperature hot water / steam temperature T of drying room 1 in real time. s chilled water temperature T f High-temperature hot water / steam volume G s chilled water volume G fAfter the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d And based on the temperature deviation f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, the opening degree of the high-temperature three-way valve is dynamically adjusted by PID control to increase the hot water flow rate entering the high-temperature drying heat exchanger 8, thereby maintaining a stable drying chamber temperature. When f T and f d When the flow rate approaches zero, the running time t is recorded. The flow rate on the heat exchange side is reduced, and excess heat is introduced into the high-temperature hot water tank 14, thereby stabilizing the output of high-temperature hot water / steam. When t ≥ t _set At this point, the system completes the high-temperature drying stage and enters the next operating stage. If the current operating condition does not require the participation of the high-temperature drying heat exchanger 8, it determines whether high-temperature hot water / steam is needed; if high-temperature hot water / steam is needed, it determines the temperature deviation from the target high-temperature hot water / steam temperature based on the required deviation. f s = (T s_set -T s ) / T s_set ×100%, PID control adjusts the compressor frequency by 10. When f s When the value is greater than 0, the compressor operating frequency is increased to improve the overall heating capacity of the system; when f s When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the high-temperature three-way valve 35 to distribute heat to the production process loop as needed. Steam valve 31 is then opened, and G is determined. s ≥G s_set If the high-temperature hot water / steam supply is not required, the process proceeds to the next stage. If no high-temperature hot water / steam supply is needed, the process proceeds to the next stage. Subsequently, the high-temperature stage refrigerant and the low-temperature stage refrigerant are depressurized by their respective throttling elements 20 and 21 before entering the high-temperature stage evaporator 19 and the low-temperature stage evaporator 17. The high-temperature stage evaporator 19 continues to act as a cascade heat exchanger to absorb the heat released by the low-temperature stage system. The low-temperature stage evaporator 17 produces chilled water through the chilled water pump 24 and sends it to the chilled water heat exchanger 5 through the chilled water three-way valve 32 to cool and dehumidify the humid air, causing water vapor in the air to condense and be discharged from the system. During operation, if the chilled water heat exchanger 5 needs to be started, the temperature deviation will be considered. f T = (T _set -T) / T _set×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100% PID control is applied to the dehumidification process. f T and f d When both are less than 0, the PID control system prioritizes increasing the opening of the chilled water three-way valve 32 to improve the heat exchange capacity of the chilled water; when f T and f d When the dehumidification time approaches 0, start recording the running time t and maintain stable operation at the current dehumidification state; when t ≥ t _set When the system completes this phase of operation, it proceeds to the next phase. If the current operating conditions do not require the participation of chilled water heat exchanger 5, the system determines whether there is a chilled water requirement in the production process; if there is a chilled water requirement, it determines the chilled water temperature deviation from the target. f f = (T f_set -T f ) / T f_set ×100%, PID control adjusts the compressor frequency. When f f When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall cooling capacity of the system; when... f f When the temperature approaches 0, the PID control compressor operates stably, adjusting the opening of the chilled water three-way valve 32 to distribute the cooling capacity to the production process loop as needed, and turning on the chilled water supply pump 28 to determine G. f ≥G f_set If the supply of chilled water is not required, the process will stop and proceed to the next stage.

[0041] Since all the heat and cold in the system are used for high-temperature drying during the cascade operation, this stage prioritizes meeting the drying process requirements and does not provide heat and cold to assist the coconut juice production process.

[0042] 3) Maillard reaction After the material has been dehydrated, the Maillard reaction requires a controlled temperature of 125–145°C and does not require dehumidification. To ensure efficient operation of the unit at a low pressure ratio, the high-temperature stage system is activated to produce 125–150°C hot water to provide heat for the Maillard reaction (cold water is used to assist in cooling after cooking). Simultaneously, the low-temperature stage system can be activated to produce 80–90°C medium-temperature hot water to provide auxiliary heat for pasteurization and 10–25°C chilled water to provide cooling after pasteurization.

[0043] When the high-temperature stage system is started for Maillard reaction heating, the high-temperature stage compressor 10 operates, and the refrigerant releases heat through the high-temperature stage condenser 18. High-temperature hot water is then delivered by the high-temperature water pump 27. The high-temperature three-way valve 35 is controlled to prioritize the delivery of the high-temperature hot water to the high-temperature drying heat exchanger 8 to provide heat for the Maillard reaction. The target air temperature T in the drying chamber 1 is set. _set (e.g., T) _set =145℃), target dew point temperature T d_set (e.g., T) d_set =25℃), target temperature T for high-temperature hot water / steam s_set (e.g., T) s_set =150℃), target temperature of cold water T c_set (e.g., T) c_set =25℃), target quantity of high-temperature hot water / steam G s_set (e.g. G) s_set =10t), target cold water volume G c_set (e.g. G) c_set =10t), target running time t after the condition is met _set (e.g. t) _set =3h), and monitor the high-temperature hot water / steam temperature T of drying room 1 in real time. s Cold water temperature T c Steam quantity G m Cold water volume G c After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d And based on the temperature deviation f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, when f T Greater than 0 f d When the value is less than 0, the PID control system prioritizes the opening of the high-temperature three-way valve to 35 degrees to improve the heat exchange capacity of the high-temperature water; when... f T and f d When the flow rate approaches zero, the running time t is recorded, the heat exchanger flow rate is reduced, and excess heat is introduced into the high-temperature hot water tank 14, thereby stabilizing the output of high-temperature hot water / steam. When t ≥ t _setWhen the current process stage is completed, the system determines that it is ready to proceed to the next stage or stop operation. If the current operating condition does not require the participation of the high-temperature drying heat exchanger 8, it determines whether high-temperature hot water / steam is needed; if high-temperature hot water / steam is needed, it determines the temperature deviation from the target based on the required temperature. f s = (T s_set -T s ) / T s_set ×100%, PID control adjusts the compressor frequency by 10. When f s When the value is greater than 0, PID control increases the compressor's operating frequency to improve the overall heating capacity of the system; when... f s When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the high-temperature three-way valve 35 to distribute heat to the production process loop as needed. Steam valve 31 is then opened, and G is determined. s ≥G s_set If the high-temperature hot water / steam supply is not required, the process proceeds to the next stage. The refrigerant, after being depressurized by the throttling element 21, enters the high-temperature evaporator 19 to absorb heat, and is then supplied with chilled water by the chilled water pump 26. When the chilled water heat exchanger 7 needs to be activated, the temperature deviation is set. f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, when f T and f d When all values ​​are less than 0, the PID control system prioritizes increasing the opening of the chilled water three-way valve 34 to improve the chilled water heat exchange capacity; when f T and f d As the temperature approaches zero, the running time t is recorded. PID control reduces the opening of the three-way valve to avoid overcooling while maintaining stable dehumidification boundary conditions. This achieves coordinated control of the drying chamber temperature and dew point, allowing coconut meat dehydration and air dehumidification to proceed simultaneously, completing closed-loop drying without the need for dehumidification. When t ≥ t _set If the current operating condition does not require the participation of the chilled water heat exchanger 7, the system determines whether there is a need for chilled water in the production process; if chilled water is required, the system determines the chilled water temperature deviation from the target. f c = (T c_set -T c ) / T c_set×100%, PID control adjusts the compressor frequency by 10. When f c When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall cooling capacity of the system; when... f c When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the chilled water three-way valve 34 to distribute the cooling capacity to the production process loop as needed, providing cooling capacity for post-cooking cooling. The chilled water supply pump 30 is then turned on, and G is determined. c ≥G c_set If the cold water supply stops, proceed to the next stage.

[0044] Subsequently, the cryogenic stage system is started, and the cryogenic stage compressor 9 operates. The first solenoid valve 22 is closed, and the second solenoid valve 23 is opened. The refrigerant-side heat exchanger 15 does not exchange heat. The refrigerant releases heat through the cryogenic stage condenser 16. The system first sets the target air temperature T in the drying chamber 1. _set (e.g., T) _set =145℃), target dew point temperature T d_set (e.g., T) d_set =15℃), target temperature T for medium-temperature hot water m_set (e.g., T) m_set =90℃), target temperature of chilled water T f_set (e.g., T) f_set =10℃), target water volume for medium-temperature hot water G m_set (e.g. G) m_set =10t), target chilled water volume G f_set (e.g. G) f_set =10t), after the condition is met, the target running time t _set (e.g. t) _set =3h), and monitor the temperature T of the medium-temperature hot water in drying room 1 in real time. m chilled water temperature T f Medium-temperature hot water volume G m chilled water volume G f After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d There is a demand for medium-temperature hot water; the deviation from the target medium-temperature hot water temperature will be considered. f m = (T m_set -T m ) / T m_set ×100%, PID control adjusts the compressor frequency. When f f When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall heating capacity of the system; when... f fWhen the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the medium-temperature water three-way valve 33 to distribute heat to the production process loop as needed. The medium-temperature water supply pump 29 is then turned on, delivering medium-temperature hot water to the pasteurization equipment to provide heat for pasteurization. (The last sentence appears to be incomplete and possibly refers to a separate process: "Judging G...") m ≥G m_set If the refrigerant pressure is reduced by the throttling element 20, it enters the low-temperature evaporator to absorb heat. At this point, there is a demand for chilled water, which is determined based on the deviation of the chilled water temperature target. f f = (T f_set -T f ) / T f_set ×100%, PID control adjusts the compressor frequency. When f f When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall cooling capacity of the system; when... f f When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the chilled water three-way valve 32 to distribute cooling capacity to the production process loop as needed. The chilled water supply pump 28 is then turned on, delivering chilled water to the post-pasteurization cooling equipment to provide cooling capacity for post-pasteurization cooling. (Judgment G) f ≥G f_set If the supply of chilled water stops, the process will proceed to the next stage.

[0045] 4) Product cooling process After the Maillard reaction is complete, the coconut meat and drying equipment need to be gradually cooled. To avoid condensation from rapid cooling affecting product quality, the coconut meat and drying equipment are cooled in stages. In the first stage, when the material temperature is high, the high-temperature stage system is activated for cooling. The high-temperature stage compressor 10 runs, and the refrigerant releases heat through the high-temperature stage condenser 18, setting the target air temperature T in the drying chamber 1. _set (e.g., T) _set =50℃), target dew point temperature T d_set (e.g., T) d_set =15℃), target temperature T for high-temperature hot water / steam s_set (e.g., T) s_set =50℃), target temperature of cold water T c_set (e.g., T) c_set =50℃), target quantity of high-temperature hot water / steam G s_set (e.g. G) s_set =10t), target cold water volume G c_set (e.g. G) c_set =10t), target running time t after the condition is met _set (e.g. t) _set =3h), and monitor the high-temperature hot water / steam temperature T of drying room 1 in real time. sCold water temperature T c Steam quantity G m Cold water volume G c After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d If high-temperature hot water / steam is required, the deviation from the target temperature for high-temperature hot water / steam will be considered. f s = (T s_set -T s ) / T s_set ×100%, PID control adjusts the compressor frequency by 10. When f s When the value is greater than 0, PID control increases the compressor's operating frequency to improve the overall heating capacity of the system; when... f s When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the high-temperature three-way valve 35 to distribute heat to the production process loop as needed. Steam valve 31 is then opened, and G is determined. s ≥G s_set If the high-temperature hot water / steam delivery stops, the process proceeds to the next stage. The refrigerant, after being depressurized by the throttling element 21, enters the high-temperature evaporator 19 to absorb heat, delivering chilled water to the cooling heat exchanger 7, where the temperature deviation is set. f T = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set ×100%, when f T and f d When all values ​​are less than 0, the PID control system prioritizes increasing the opening of the chilled water three-way valve 34 to improve the chilled water heat exchange capacity; when f T and f d As the temperature approaches zero, the running time t is recorded. PID control reduces the opening of the three-way valve to avoid overcooling while maintaining stable dehumidification boundary conditions. This achieves coordinated control of the drying chamber temperature and dew point, allowing coconut meat dehydration and air dehumidification to proceed simultaneously, completing closed-loop drying without the need for dehumidification. When t ≥ t _set If the system determines whether there is a need for chilled water in the production process, and if no chilled water supply is required, it proceeds to the next stage.

[0046] In the second stage, when the temperature of the coconut meat and drying room drops below 60℃, it needs to be cooled again to around 20-30℃. Therefore, the low-temperature stage system is activated to produce chilled water at 10-25℃ to provide cooling for the materials in the drying room (the warm water provides auxiliary heat for pasteurization). The low-temperature stage compressor 9 operates, controlling the first solenoid valve 22 to close and the second solenoid valve 23 to open. The refrigerant-side heat exchanger 15 does not participate in heat exchange. The refrigerant releases heat through the low-temperature stage condenser 16. The system first sets the target air temperature T in the drying room 1. _set (e.g., T) _set =60℃), target dew point temperature T d_set (e.g., T) d_set =20℃), target temperature T for medium-temperature hot water m_set (e.g., T) m_set =60℃), target temperature of chilled water T f_set (e.g., T) f_set =20℃), target water volume for medium-temperature hot water G m_set (e.g. G) m_set =10t), target chilled water volume G f_set (e.g. G) f_set =10t), after the condition is met, the target running time t _set (e.g. t) _set =3h), and monitor the temperature T of the medium-temperature hot water in drying room 1 in real time. m chilled water temperature T f Medium-temperature hot water volume G m chilled water volume G f After the conditions are met, the operating time t, the drying oven temperature T, and the air dew point temperature T are all considered. d If there is a demand for medium-temperature hot water, the temperature deviation will be determined based on the target temperature deviation. f m = (T m_set -T m ) / T m_set ×100%, PID control adjusts the compressor frequency. When f f When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall heating capacity of the system; when... f f When the temperature approaches 0, the PID-controlled compressor operates stably, adjusting the opening of the medium-temperature water three-way valve 33 to distribute heat to the production process loop as needed. The medium-temperature water supply pump 29 is then turned on, supplying medium-temperature hot water to the pasteurization equipment for circulation, providing heat for pasteurization. (G is then determined.) m ≥G m_set If the temperature is too high, the supply of medium-temperature water will stop, and the process will proceed to the next stage. After the refrigerant is depressurized by the throttling element 20, it enters the low-temperature evaporator 17 to absorb heat. During this process, the chilled water heat exchanger 5 needs to be started, depending on the temperature deviation. fT = (T _set -T) / T _set ×100% and dew point deviation f d = (T d_set -T d ) / T d_set The dehumidification process is controlled at 100%. f T and f d When all values ​​are less than 0, the PID control system prioritizes increasing the opening of the chilled water three-way valve 32 to improve the heat exchange capacity of the chilled water; when f T and f d When the dehumidification time approaches 0, start recording the running time t and maintain stable operation at the current dehumidification state; when t ≥ t _set When the system completes this phase of operation, it proceeds to the next phase. The system determines that there is a demand for chilled water and determines this demand based on the deviation from the chilled water temperature target. f f = (T f_set -T f ) / T f_set ×100%, PID control adjusts the compressor frequency. When f f When the value is less than 0, the PID control increases the compressor's operating frequency to improve the overall cooling capacity of the system; when... f f When the temperature approaches 0, the PID control compressor operates stably, adjusting the opening of the chilled water three-way valve 32 to distribute the cooling capacity to the production process loop as needed, and turning on the chilled water supply pump 28 to determine G. f ≥G f_set If the supply of chilled water stops, the process will proceed to the next stage.

[0047] 5) Operation of other production processes Once the coconut meat is processed, and there is no need to supply cooling or heating to the drying room 1, the corresponding functions can be activated according to the production needs of coconut juice.

[0048] This specific embodiment proposes an independent / cascade switchable architecture. Through the arrangement of the refrigerant-side heat exchanger and solenoid valves at both ends, it achieves flexible decoupling and recoupling of the low-temperature and high-temperature stage systems. It can independently output medium-temperature heating and cooling, high-temperature steam, and chilled water on the same equipment, and can also progressively increase the heat quality to produce high-temperature steam. At the control level, a two-dimensional control strategy is introduced, which adjusts the compressor frequency based on the target temperature deviation and switches the three-way valve conduction direction based on the dew point deviation. This allows the system to dynamically switch operating modes and allocate energy on demand according to the heating and cooling needs of different production stages. This breaks through the limitations of conventional heat pumps operating under a single condition, improving the flexibility, temperature range coverage, and adaptability of combined cooling and heating systems.

[0049] Example 2 This embodiment discloses an operation control method for a wide-temperature-range cascade multifunctional industrial heat pump system, including a low-temperature stage system operation mode, a high-temperature stage system operation mode, and a cascade system operation mode. In the independent operation mode of the low-temperature stage, the low-temperature stage compressor is started, allowing the refrigerant to circulate in the low-temperature stage subsystem; the heat output of the low-temperature stage condenser is selected to the medium-temperature hot water tank or the medium-temperature drying heat exchanger through the medium-temperature water three-way valve, and the low-temperature stage evaporator absorbs heat from the chilled water tank or the chilled water heat exchanger through the refrigeration three-way valve; the operating frequency of the low-temperature stage compressor is adjusted according to the first target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the independent operation mode of the high-temperature stage, the high-temperature stage compressor is started, allowing the refrigerant to circulate in the high-temperature stage subsystem; the high-temperature three-way valve is used to select whether the heat from the high-temperature stage condenser is output to the high-temperature hot water tank or the high-temperature drying heat exchanger, and the cold water three-way valve is used to select whether the high-temperature stage evaporator absorbs heat from the cold water tank or the cold water heat exchanger; the operating frequency of the high-temperature stage compressor is adjusted according to the second target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the cascade operation mode, the low-temperature stage compressor and the high-temperature stage compressor are started simultaneously, and the refrigerant-side heat exchanger is controlled to participate in heat exchange. The heat absorbed by the low-temperature stage subsystem is transferred to the high-temperature stage subsystem through the refrigerant-side heat exchanger, and then output after being upgraded by the high-temperature stage subsystem. The heat is output to the high-temperature hot water tank through the high-temperature three-way valve, and the cold energy is output to the chilled water tank through the refrigeration three-way valve. The operating frequency of each compressor is adjusted according to the third target temperature deviation.

[0050] Example 3 This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the operation control method described in Embodiment 2 above.

[0051] Example 4 This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the operation control method described in Embodiment 2 above.

[0052] The steps or modules involved in Embodiments 2 to 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wide-temperature-range cascade multifunctional industrial heat pump system, characterized in that, include: The cryogenic stage subsystem consists of a cryogenic stage compressor, a cryogenic stage condenser, a cryogenic stage throttling element, and a cryogenic stage evaporator connected in sequence to form a loop. The water-side interface of the low-temperature stage condenser is selectively connected to a medium-temperature hot water tank or a medium-temperature drying heat exchanger via a medium-temperature water three-way valve; the water-side interface of the low-temperature stage evaporator is selectively connected to a chilled water tank or a chilled water heat exchanger via a chilled water three-way valve. The high-temperature stage subsystem consists of a high-temperature stage compressor, a high-temperature stage condenser, a high-temperature stage throttling element, and a high-temperature stage evaporator connected in sequence to form a loop; the water-side interface of the high-temperature stage condenser is selectively connected to a high-temperature hot water tank or a high-temperature drying heat exchanger via a high-temperature three-way valve; the water-side interface of the high-temperature stage evaporator is selectively connected to a cold water tank or a cold water heat exchanger via a cold water three-way valve. The cascade heat exchange unit includes a refrigerant-side heat exchanger, whose low-temperature side passage is connected between the outlet of the low-temperature stage compressor and the low-temperature stage condenser, and the two ends of the passage are respectively provided with solenoid valves, and whose high-temperature side passage is connected between the high-temperature stage evaporator and the suction port of the high-temperature stage compressor. The room includes a drying / refrigeration area with a room body equipped with air supply and return vents. The medium-temperature drying heat exchanger, chilled water heat exchanger, high-temperature drying heat exchanger, and cold water heat exchanger are all located within the room body or connected to its air duct.

2. The wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, When the system is in the medium-temperature drying condition, the medium-temperature water three-way valve connects the water-side interface of the low-temperature stage condenser to the medium-temperature drying heat exchanger. The refrigerant discharged from the low-temperature stage compressor releases heat through the low-temperature stage condenser, and the heat is transferred to the medium-temperature drying heat exchanger through water circulation. The refrigeration three-way valve connects the water-side interface of the low-temperature stage evaporator to the chilled water heat exchanger. The refrigerant absorbs heat in the low-temperature stage evaporator, and the cooling capacity is transferred to the chilled water heat exchanger through water circulation.

3. The wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, When the system is in medium-temperature hot water supply mode, the medium-temperature water three-way valve connects the water-side interface of the low-temperature stage condenser to the medium-temperature hot water tank. The refrigerant discharged by the low-temperature stage compressor releases heat through the low-temperature stage condenser, and the heat is stored in the medium-temperature hot water tank through water circulation. The chilled water three-way valve connects the water-side interface of the low-temperature stage evaporator to the chilled water tank. The refrigerant absorbs heat in the low-temperature stage evaporator, and the cooling capacity is stored in the chilled water tank through water circulation.

4. The wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, When the system is in high-temperature drying mode, the high-temperature three-way valve connects the water-side interface of the high-temperature stage condenser to the high-temperature drying heat exchanger. The refrigerant discharged from the high-temperature stage compressor releases heat through the high-temperature stage condenser, and the heat is transferred to the high-temperature drying heat exchanger through water circulation. The cold water three-way valve connects the water-side interface of the high-temperature stage evaporator to the cold water heat exchanger. The refrigerant absorbs heat in the high-temperature stage evaporator, and the cooling capacity is transferred to the cold water heat exchanger through water circulation.

5. The wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, When the system is in steam or high-temperature hot water production mode, the high-temperature three-way valve connects the water-side interface of the high-temperature stage condenser to the high-temperature hot water tank. The refrigerant discharged from the high-temperature stage compressor releases heat through the high-temperature stage condenser, and the heat is stored in the high-temperature hot water tank through water circulation and used to produce steam. The cold water three-way valve connects the water-side interface of the high-temperature stage evaporator to the cold water tank. The refrigerant absorbs heat in the high-temperature stage evaporator, and the cooling capacity is stored in the cold water tank through water circulation.

6. The wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, When the system is in cascade operation, the solenoid valves at both ends of the low-temperature side passage of the refrigerant-side heat exchanger are switched to the conducting state. The refrigerant discharged from the low-temperature stage compressor first flows through the refrigerant-side heat exchanger to release heat, and then enters the low-temperature stage evaporator through the low-temperature stage throttling element. The high-temperature stage evaporator absorbs heat from the low-temperature stage system through the high-temperature side passage of the refrigerant-side heat exchanger, and after being compressed by the high-temperature stage compressor, it enters the high-temperature stage condenser to release heat; the high-temperature three-way valve connects the water-side interface of the high-temperature stage condenser to the high-temperature hot water tank to produce steam, and the refrigeration three-way valve connects the water-side interface of the low-temperature stage evaporator to the chilled water tank to produce chilled water.

7. A method for operating and controlling a wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 1, characterized in that, The method includes a low-temperature stage system operation mode, a high-temperature stage system operation mode, and a cascade system operation mode; In the independent operation mode of the low-temperature stage, the low-temperature stage compressor is started, so that the refrigerant circulates in the low-temperature stage subsystem; The heat output of the low-temperature stage condenser to the medium-temperature hot water tank or the medium-temperature drying heat exchanger is selected by the medium-temperature water three-way valve, and the heat absorption of the low-temperature stage evaporator from the chilled water tank or the chilled water heat exchanger is selected by the refrigeration three-way valve; the operating frequency of the low-temperature stage compressor is adjusted according to the first target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the independent operation mode of the high-temperature stage, the high-temperature stage compressor is started, allowing the refrigerant to circulate in the high-temperature stage subsystem; the high-temperature three-way valve is used to select whether the heat from the high-temperature stage condenser is output to the high-temperature hot water tank or the high-temperature drying heat exchanger, and the cold water three-way valve is used to select whether the high-temperature stage evaporator absorbs heat from the cold water tank or the cold water heat exchanger; the operating frequency of the high-temperature stage compressor is adjusted according to the second target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions; In the cascade operation mode, the low-temperature stage compressor and the high-temperature stage compressor are started simultaneously, and the refrigerant-side heat exchanger is controlled to participate in heat exchange. The heat absorbed by the low-temperature stage subsystem is transferred to the high-temperature stage subsystem via the refrigerant-side heat exchanger, and then output after being upgraded by the high-temperature stage subsystem. The heat is output to the high-temperature hot water tank through the high-temperature three-way valve, and the cold energy is output to the chilled water tank through the refrigeration three-way valve. The operating frequency of each compressor is adjusted according to the third target temperature deviation, and the conduction direction of each three-way valve is switched according to the environmental conditions.

8. The operation control method for the wide-temperature-range cascade multifunctional industrial heat pump system as described in claim 7, characterized in that, The first target temperature deviation includes the target deviation of medium-temperature hot water temperature, chilled water temperature, temperature deviation, and dew point deviation; The second target temperature deviation includes the steam temperature target deviation, cold water temperature, temperature deviation, and dew point deviation; The third target temperature deviation includes steam temperature target deviation, chilled water temperature, temperature deviation, and dew point deviation.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the operation control method as described in any one of claims 7-8.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the operation control method as described in any one of claims 7-8.

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